Skip to content
Woodworking Masterclasses
Facebook Instagram
  • Register Now
  • Video Library
  • GalleryExpand
    • Bedside Cabinet GalleryExpand
      • Assembly Table Gallery
      • Bathroom Cabinet Gallery
      • Bench Stool Gallery
      • Blanket Chest Gallery
      • Bookends Gallery
      • Book Shelves Gallery
      • Breadboard-end Cutting Board Gallery
      • Carrying Tote Gallery
      • Chess Board Gallery
      • Chest of Drawers Gallery
      • Christmas Gallery
      • Coasters Gallery
      • Coat Rack Gallery
      • Coffee Table Gallery
      • Corner Shelf Gallery
      • Craftsman-style Lamp Gallery
      • Dining Chair Gallery
      • Dovetail Boxes Gallery
      • Fly Swat Gallery
      • Frame Saw Gallery
    • Foot Stool GalleryExpand
      • How to Make a Table
      • Joiner’s Mallet Gallery
      • Joiners’ Toolbox Gallery
      • Keepsake Box Gallery
      • Laptop Desk Gallery
      • Leaning Wall Shelf Gallery
      • Mitre Box Gallery
      • Occasional Table Gallery
      • Picture Frames Gallery
      • Rocking Chair
      • Sawhorse Gallery
      • Shaker-Style Bench Seat Gallery
      • Shaker Stool Gallery
      • Sofa Table Gallery
      • Stepladder Gallery
    • Trestle TableExpand
      • Tool Cabinet
      • Tool Chest Gallery
      • Walking Cane Gallery
      • Wall Brackets Gallery
      • Wallclock Gallery
      • Wall Shelf Gallery
      • Winding Sticks Gallery
      • Wooden Plane Gallery
      • Wooden Spokeshave
      • Wooden Tray Gallery
      • Workbench Gallery
      • Other user projects vol. I
      • Other user projects vol. II
      • Submit Photos to Gallery
  • About Us
  • News
  • FAQsExpand
    • General FAQs
    • Workbench FAQs
  • Contact
Account Login
Woodworking Masterclasses

Reply To: Motors and thermal protection

Welcome! / Forums / General Woodworking Discussions / Tools and Tool Maintenance/Restoration / Motors and thermal protection / Reply To: Motors and thermal protection

Joost Borst
13 September 2021 at 5:46 pm #728575

I am a bit rusty on motor theory but ill give it a go, learned so much here its the least I can do. 🙂

I’m not really familiar on how its done in the USA but a basic 1 phase motor has a capacitor in it to create a phaseshift.

If you look at the schematic it has the two main wires comming into the motor connected to a coil. There is another connection to a capacitor that feed into another coil that is physiclly at a different angle around the rotor (moving part). What bassicly happens is that the capacitor will delay the current going to the second coil by storing it. A capacitor is like a bucket with a hole in it.

So if you look at my really bad paint drawing 😉 you get your normal coil in the green and than the second coil in red.
There are a type of magnet in the rotor that will try to allign it self with the magnetic field created by the coils causing it to rotate. Since one of the coils is shifted in time the magnetic field will shift position causing the rotor to keep moving. Kinda like a dog chasing its tail.

If the capacitor is broken it cant make the phase shift so there isnt any delay, no delay means no rotation.
The motor will still draw power but wont rotate, the power has to go somewhere so it will turn in to heat. The fact that normally there is a cooling fan attached to the rotor it will overheat even quicker cause the fan isnt spinning.

I’m gonna agree with the others that probably the cheapest and most logical fix is gonna be to change the capacitor. Try finding someone that has a good knowledge of electric motors to help you out. Maybe ask him to measure the windings of the motor while your at it, isolation does degrade over the years and can cause shorts in the motor.

If your still wondering about the thermal protection, motors these days are usually equipt with Clixons or thermistors. A clixon is basicly a bi-metal switch that will switch once the motor is to hot and resets it self once its cooled of again. An thermistor is a heatsensitve resistor that can be used to measure the temperatuur more accurate.

Another cause of the trips can be a motor protection device (dont know the propper term in english) like a 3RV20 from Siemens. These device are like the circuit breakers in your house but they can be set to the specific motor current. They also have a pretty ingenius mechanical solution to make sure current is being drawn equally from all phases. I do doubt that that thing is in such an “experienced” machine.

Just to make it clear, if you dont know what your doing, dont mess with electricity it can hurt/kill you.

Attachments:
You must be logged in to view attached files.
Settings

About Our Company

Woodworking Masterclasses is a trading name of Rokesmith Ltd

Rokesmith Ltd



About Rokesmith Ltd | Privacy Policy | Terms and Conditions | About Us


Useful Links

© 2023 - Rokesmith Ltd

  • Register Now
  • Video Library
  • Gallery
    • Bedside Cabinet Gallery
      • Assembly Table Gallery
      • Bathroom Cabinet Gallery
      • Bench Stool Gallery
      • Blanket Chest Gallery
      • Bookends Gallery
      • Book Shelves Gallery
      • Breadboard-end Cutting Board Gallery
      • Carrying Tote Gallery
      • Chess Board Gallery
      • Chest of Drawers Gallery
      • Christmas Gallery
      • Coasters Gallery
      • Coat Rack Gallery
      • Coffee Table Gallery
      • Corner Shelf Gallery
      • Craftsman-style Lamp Gallery
      • Dining Chair Gallery
      • Dovetail Boxes Gallery
      • Fly Swat Gallery
      • Frame Saw Gallery
    • Foot Stool Gallery
      • How to Make a Table
      • Joiner’s Mallet Gallery
      • Joiners’ Toolbox Gallery
      • Keepsake Box Gallery
      • Laptop Desk Gallery
      • Leaning Wall Shelf Gallery
      • Mitre Box Gallery
      • Occasional Table Gallery
      • Picture Frames Gallery
      • Rocking Chair
      • Sawhorse Gallery
      • Shaker-Style Bench Seat Gallery
      • Shaker Stool Gallery
      • Sofa Table Gallery
      • Stepladder Gallery
    • Trestle Table
      • Tool Cabinet
      • Tool Chest Gallery
      • Walking Cane Gallery
      • Wall Brackets Gallery
      • Wallclock Gallery
      • Wall Shelf Gallery
      • Winding Sticks Gallery
      • Wooden Plane Gallery
      • Wooden Spokeshave
      • Wooden Tray Gallery
      • Workbench Gallery
      • Other user projects vol. I
      • Other user projects vol. II
      • Submit Photos to Gallery
  • About Us
  • News
  • FAQs
    • General FAQs
    • Workbench FAQs
  • Contact
Login Account
Search